- #1
newTonn
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Energy can be neither created nor destroyed.
What is energy?. ability to do work.
what is work ? work = force x displacement.
Consider a body of mass 'm' moving at a uniform velocity 'v'.work done here is zero(no acceleration).So energy is zero.
DONT SAY KINETIC ENERGY is there.please check the derivation of kinetic energy.
Since work = F*d
and
F = m*a
then
work = m*a*d.
From kinematics we know that
d = 1/2 * a*t2
and
t = v/a.
so d = (1/2* a *v2)/ a2 = (1/2* v2)/ a
so work = m* a * (1/2* v2)/ a = 1/2 * m * v2.
in this derivation please note that t = v/a, is only applicable when initial velocity is zero. here initial and final velocity are v ,and kinetic energy will be zero.
now come back to the point.what will happen ,if this body hits another body at rest.?(mass is irrelevant-body at rest have no energy stored,isn't it?).
After collision, both of the bodies have energy(since there is an acceleration).
from where does this energy comes from.?
What is energy?. ability to do work.
what is work ? work = force x displacement.
Consider a body of mass 'm' moving at a uniform velocity 'v'.work done here is zero(no acceleration).So energy is zero.
DONT SAY KINETIC ENERGY is there.please check the derivation of kinetic energy.
Since work = F*d
and
F = m*a
then
work = m*a*d.
From kinematics we know that
d = 1/2 * a*t2
and
t = v/a.
so d = (1/2* a *v2)/ a2 = (1/2* v2)/ a
so work = m* a * (1/2* v2)/ a = 1/2 * m * v2.
in this derivation please note that t = v/a, is only applicable when initial velocity is zero. here initial and final velocity are v ,and kinetic energy will be zero.
now come back to the point.what will happen ,if this body hits another body at rest.?(mass is irrelevant-body at rest have no energy stored,isn't it?).
After collision, both of the bodies have energy(since there is an acceleration).
from where does this energy comes from.?
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